A multi-port memory is a memory with one or more independent physical or logical interfaces that control regions, e.g., sub-portions or banks, of the memory. Each physical interface includes a control mechanism, e.g., a control bus, for receiving command and address signals, and a data bus, for communicating data signals, that control the memory operation and transport data to and from the memory. Multi-port memory are of interest due to their ability to reduce power and latency of memory operation by being able to independently control separate regions of the memory.
Nonvolatile memory is an important form of semiconductor memory. Non-volatile memory generally holds its data values for some extended period without the application of power. Flash memory devices are one particular class of non-volatile memory that have developed into a popular source of memory for a wide range of electronic applications. Flash memory devices typically use a one-transistor memory cell that allows for high memory densities, high reliability, and low power consumption. Changes in threshold voltage of the cells, through programming of a charge storage node, (e.g., a floating gate or charge trap), or other physical phenomena (e.g., phase change or polarization), determine the data value of each cell. By defining two or more ranges of threshold voltages to correspond to individual data values, one or more bits of information may be stored on each cell.
Another important form of semiconductor memory includes volatile memory, such as dynamic random access memory (DRAM). Volatile memory is often used where rapid access to the memory array is desired for both data input and data output. Volatile memory, such as DRAM, generally has faster access times many non-volatile memories, but requires periodic refresh to avoid losing its data values.
Common uses for semiconductor memory include personal computers, personal digital assistants (PDAs), digital cameras, digital media players, digital recorders, games, appliances, vehicles, wireless devices, mobile telephones and removable memory modules, and the uses for non-volatile memory continue to expand. As the applications and demands for memory expand, flexibility becomes more desirable.
For the reasons stated above, and for other reasons which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for alternative multi-port memories and their operation.